Radio direction system



June 1, 1937.

Filed Nov. 28., 1953 4 Shgets-Sheet 1 --'---------I I I I I I I I---------- INVENTORS.

AUGUST LEIB HANSJCARLAU.

ATTORNEY June 1, 193,7- A.LEIBIET AL v 2,032,347

RADIO DIRECTION SYSTEM, Filed Nov. 28, 1955' 4 Sheets-Sheet 2 wzc F g', TRAMSM/TTER INVENTO R5. N AUGUST LEIB v mus swam/m: I

ATTORNEY Jun1,19 3 7; A LEIB H I 2,082,347

RADIO DIRECTION SYSTEM Filed Nov. 28, 1935, 4 Sheets-Sheet s INVENTORS AUG UST LE I B -HANS c LAU AfToR-NEY June 1, 1937. A. LEIB ET AL.

' RADIO DIRECTION SYSTEM V Filed Nov. 28, less 4 Sheds-Sheet 4 Iii/ 9.6

4/1/7' EMA/A ANTENNA vINVENTORS AUGUST LEIB HANS '5 ARLAU AT ToRNE Patented June 1, 1937 RADIO DIRECTION SYSTEM August Leib and Hans Seharlau, Berlin, Germany,

assignors to Teleiunken Gesellschaft fiir Drahtlose Telegraphie m. b. 11., Berlin, Germany, a corporation of Germany Application November 28, 1933, Serial No. 700,067 In Germany November 29, 1932 4 Claims.

This invention relates to a system for the direction of airplanes along a line.

It is well known in order to direct sea or aircrafts, to .emit two electro-magnetic radiations of ,difi'erent spacial distribution from a definite position in such manner that the geometrical location in space of all points where the reception of both radiations is of equal intensity, forms a di rection zone for the craft. Both radiations have hereby different characteristic markings such as,

dlflerent Morse signals or modulations so that the pilot is enabled of ascertaining through comparison of the receiving intensities with different indications by means of acoustic or optical indi- 5 cators whether he travels at the right or left side of the directionzone. This (so-called Scheller- Kiebitz) direction method, however, is insufllcient in order to direct an aircraft moving within three dimensions of space (in other words an airplane) along a definite line; on the other hand it is often desirable to avail oneself of such line of direction such as a line inclined towards the field of landing under a very small angle and which mayserve as landing course. 25 This invention will best be understood by referring to the accompanying drawings in which Figure 1 shows, diagrammatically, two vertical frame radiators having intersecting planes; Figure 2 shows the arrangement of different Morse 3o signals on the radiation sectors; Figure 2a. shows the arrangement of a rotating switch drum'in the developed state which controls the Morse signals;

Flgure'2b shows an uninterrupted row of Morse signals resulting from the cooperation of all 35 rows of the segments 01' the rotating switch drum; Figure 2c is a circuit diagram showing how the frame radiators are connected to the rotating switch drum; Figure 3 is a diagram ofa radiating sector. oriented in space; Figure 3a is a diagram 4 of the lamp indicator for indicating the radiating sectors; Figure 4 is a diagram of a single beam antenna unit; Figure 5 is a diagram showing the arrangement of the four beam antennas; Figure 5a is a perspective view of the arrangement of 45 the four beam antennas; Figure 6 is a diagram of the receiver circuit arrangement: Figure 7 is a perspective view of a transmitter having a single beamantenna; and Figure 815 a diagram ofthere ceiver arrangement employing four optical indi- 50 6313013.

In accordance with this invention a directing line oriented in space at any desired angle, canbe established in that a greater number than two radiation sectors emitted from approximately 55 the same point, are produced at equal wave length and which are distinguishable by means of dit ferent indications and define, within their .common zone of superposition, as directing line, the location of the points at which all radiation sectors or always two sectors within each pair produce equal receiving intensity. It is possibh, for instance (see Fig. 1) by means or two vertical frame radiators whose planes intersect along the vertical line a b, to establish in a known manner a vertical directin'g plane 0 as the plane of 'equal field intensity of the two'frame radiations, and to produce in a similar manner by means of two further frame radiators crossing each other along the, horizontal line a-d, a second directing plane 1 as location of the equal intensity of the second radiation pair and which is inclined at an angle or against the horizontal plane e. The two directing planes 0 and f intersect in line G whichmay serve as directing line. In order to control the deviation of the aircraft from this directing line, its receiver can be provided with two optical indicators known assuch. In modulating for instance the radiation producing the directing plane 0 by means of .two audio-frequencies m and m, at the out-put of the receiver, the energies corresponding to the two modulations can be separated by the use of suitably tuned filters whereafter they can be differentially supplied to an A. C. instrument, or to a D. C. instrument after rectification and in such a manner that at equal receiving intensity (i. e., when the aircraft travels in the directing plane) the pointer of the indicator remains in its central position while at a deviation of the aircraft towards the left or right side of this plane, the pointer moves correspondingly towards the left or the right. In'like manner a second indicator, diiierentlally controlled by energies with modulating frequencies m and m respectively, can be provided for the directing plane I preferably with a pointer moving relative to a vertical scale whereby its deviations from the middle position upwards or downwards indicate that the aircraft-travels above or below the directing plane I.

' It is, obvious that instead of frame radiators, also other radiators with a more distinct di-'- rectional efiect,-can be used, such as di-poles with parabolic reflectors or other known radiators with sharp concentration. It is only essential that the radiating beams are formed in such manner that all of them or alwaystwoof them within each pair produce the same receiving intensity in the directing line. a

It is also possible to render the radiation sectors distinguishable from each otherin the known manner by means of different Morse signals instead of different modulations. It may be assumed for instance (see Fig.2) that two radiations s1 and s2 produce a directing plane 0 (represented in Figure 2 by the intersection line of this plane with the drawing plane directed at right angles to the direction of propagation of the radiation) and that the other two radiations s3 and s4 produce the other directing plane represented by the intersection line I with the plane of the drawing, and that the four radiations are controlled by means of a rotating switch drum shown in Figure 2a in the developed state, namely, the radiations s1, s2, s3, s4 by means of the respective rowsof segments *l, 2, 3, 4 respectively. In this case the sequence and the duration of the single signals or different radiations is determined by the length and the disposition of the contact segments in a clearly distinguishable manner. If the airplane resides in a lateral position with respect to the directing line G withinthe space quadrant-l, 3, the signals of radiations I and 3 are better audible than the others and thus the Morse signal resulting from thecooperation of segments I and 3 and shown in Figure 2 in the quadrant l, 3,- is particularly loud. In like manner the other quadrants l, 4, or 2, 4 or 2, 3 respectively are characterized by a particularly sharp penetration of the Morse signals resulting from the cooperation of the respective segments and indicated in Figure 2 in these quadrants. In this manner the pilot can recognize in whatever quadrant he resides. If however he travels upon the directing line G, the indications of the signals of all four radiations are received at equal strength, so that in this case an uninterrupted row of signals is produced as shown in Figure 2b and resulting from thecooperation of all rows of the segments of the switch drum.

In Figure 20, S denotes the rotating switch drum in which the conducting segments are indica'ted in black. The switch drum is provided with wiping brushes B1, B2, B3 and B4 which are included in the circuits of the antennas A1, M, A: and A4, respectively, the said antenna circuits bei g coupled with the transmitter by means of transformers K1, K2, K1 and K4.

If modulation serves as indication for the single radiation sectors, an optical indication method may be used with advantage, and in which the energies corresponding to the different modulations and appearing at the receiver out-put, are separated and supplied to different lamps which are so arranged in a circle, that they represent the spacial distribution of the different radiation sectors so that equal brightness of the lamps indicate that the aircraft is upon the directing line while at unequal brightness the lamp most illuminated indicates the radiation beam transmitted to the receiving antenna at greatest intensity. V This optical indication method will later be more elaborately explained in connection with another embodiment in which different sector radiations are produced by deviating a radiation beam.

It is not absolutely necessary to produce the different radiation sectors by a corresponding number of independent radiations -fixedly oriented in space and filling these sectors. It is possible to produce the different radiation sectors by correspondingly deviating one and the same radiation beam. into .various positions and to provide different modes of indication correspondlimiting surface forms at its intersection with the drawing plane a limiting line k, is so deflected that its central axis It moves around the directing line G in the enveloping surface of a cone m, the intersection of which with the drawing plane is represented by the circle m. This movement can be continuous so that the axis 21. ofthe beam passes about the enveloping surface m at uniform rotation. However, this movement may also be performed in steps so that during each rotation it ceases in succession during a certain short time for a finite number of positions.

The manner in which the deviations of the radiating beam is obtained, is immaterial. This depends essentiallyupon the manner in which the radiating beam is produced. If it is produced by means of a parabolic reflector the desired movement of the beam can be accomplished by mechanical means, for instance, by correspondingly turning the reflector. In case of sufficiently small dimensions of the radiator and large dimensions of the reflector the former need not be disposed with absolute accuracy in the focal point but may be arranged in the proximity thereof, and in case of a fixed refiector it may move about the focal point preferably so that the plane of polarization does not.

change.

If as is indicated in Figure 4, the radiating beam is produced by a number of small di-poles t,

fed from suitable points of the Lecher in-put leads I, such arrangement permits of deviating of the radiating beam by electrical means, for in stance in connecting some of the di-poles according to a definite sequence by means of a suitable switching device, thus influencing the directional axis of the radiating beam. In this case the plane of polarization remains constant.

According to the following explanation it is assumed that 4 space sectors are used to which correspond different modulations of the radiating beam. Obviously this number could also be greater. {It isthus assumed that as long as the axis 11. of the radiating beam remains'upon the .such manner that the lamps l, o, r and u '(see Fig. 3a) are fed by the energies separated from each other at the receiver out-put and which correspond to the modulations 111, no, 71:, and nu respectively, and that these lamps are so oriented about the center point g of the annular surface in which they are arranged, as the corresponding space quadrants, L, O, R and U about the directing line G.

If the aircraft happens to be in a point F within the left space quadrant and approximately in the proximity of the center of the angle of the quadrant, the lamp 1 will be fed by the energy for such length of time as modulation of the radiating beam n1 takes place, i. e., during the durabeam passes through those points of the circuit m.

within the quadrant 0, whose distance from F is smaller than the radius of circuit k.

Lamp u for the indicated position F of the aircraft, receives its energy corresponding to modulatlon nu during a still shorter period of time than lamp 0.

Lamp 1 is not supplied with energy at all.

Hence in the indicated position of the aircraft, lamp 2 has the greatest brightness, lamp '0 is lighted darker and lamp u still darker.

The flickering of the lamps can be avoided through suitable heat inertia of the filaments and through a sulficientiy rapid speed of rotation of the radiating beam.

If the aircraft resides upon the center line of the angle of the quadrant L, lamps o and u are equally bright but darkerthan lamp 1. If point F moves approximately upon line GT, lamp 1 has the greatest brightness at thepassing through circle m and loses light at increasing distance from this circle until it becomes entirely dark in the proximity of point '1 at the limit of the beam. The lamps o and u extinguish stillearlier. Upon the limiting lines between the two quadrants, for instance between L and O, lamps l ando are of equal brightness, the other two are either darker or are not lighted at all, depending upon the distance of the aircraft from the directing line G.

- at equal illuminating powerbut are only of equal brightness if the airplane is just upon the direct lng line G.

In order to facilitate observation of the lamp indicator by the pilot the lamps may be covered by an annular screen of frosted glass whose degree of illumination changes relatively in a uniform manner from place to place (the uniformity can be further increased by increasing the number of sectors, the corresponding modulating frequencies and the indicator lamps). The direction be tween the center point a of the optical indicator and the most illuminated spot of the frosted glass plate indicates the spacial direction in which the position of the airplane deviates from the directing line G, so that the opposite direction between the most illuminated spot of the frosted glass plate to its center point 0 is an indication for the pilot guiding him in approaching the directing line.

By this arrangement the pilot's attention is completely alleviated. The only point he has to keepin mind is the rule to fly from the most illuminated spot towards the center point." Since I the slogan Towards the brightest spot" is yet to be preferred as being still more impressive to the memory, it is advisable to adapt the optical indlcator to this rule in that all lamps are turned around the center point a at 180 within the plane of their circle.

Various wave lengths can be employed -in the described wire system. In order to obtain a particularly sharp concentration, ultrashort waves, in particular decimeter waves, are preferable .at any case.

We claim:

1. A system for directing aircraft, having means including a pair of antennae for directing two beams of radiation in a vertical plane, two other antennae adapted to emit energy each in a directed beam the axis of which lies in an inclined plane perpendicular to said vertical plane, and means for so modulating the energy radiated by the respective antennae that digression of an aircraft-mounted receiver from the line of intersection of the two said planes is denoted by an increased intensity of reception of the modulation which is directed toward the particular sector in which the aircraft files.

2. In a system of the class described, a directional beam transmitter having means for causing the axis of a directed beam to describe a path substantially conformed to a conical surface, means for impressing upon said beam modulations which are dlflerently characterized as the beam axis describes each of a plurality of arcs of the conical surface, and means including a receiving device mounted on an aircraft for detecting the intensity of the received energy and for denoting the particular conical sector in which the airplane flies when it deviates from the axis of said conical surface.

3. A system in accordance with claim 2 and having means including illuminable indicators arranged in a circle and means responsive to the received modulations for causing one of said indicators to be lighted at a greater intensity than the others for indicating the direction "or deviation of the aircraft from the conical axis.

4. In a radio beacon for defining a course to be -followed by an airplane, a radio transmitter including means for directing radiations in different paths whose axes lie along the imaginary surface of a cone, said transmitter being at the apex of said cone and the conical axis being substantially coincident with said course. means for differentially. characterizing the radiations along different sectors of said conical surface, and means carried aboard the airplane for detecting the characteristics of said radiations and for indicating specifically the vertical or lateral divergenceof-said airplane from said course.

AUGUST LEIB. HANS BCHARLAU. 

